From what I can determine, the physical dimensions are the same in either case. However, the internal gearing is most probably different. The planetary gear set output shaft has a ratio or either 1.82:1 or 1.76:1 depending on engine application (lower torque vs. higher torque).

Don't forget that there are also some Powerglide transmissions out there that were designed for 4-cylinder Novas. Those are identifiable by the presence of four fairly large holes (2"?) drilled in the bellhousing, two on each side. I believe that they were not equipped with an external transmission cooler and the holes served to bleed heat off the converter. Also, if memory serves correctly, there were some early Powerglides that had a shorter tail shaft and housing. I have found those in the X-frame, full-size cars, pre-1965.

Thanks for the info Richard and "C". Just curious to know if there was any real difference in the build up of the "glide" for the 6 and v8. From what I can find and what has been mentioned here, there doesn't seem to be any real major differences.